Light screening photographic layer



A MWA Dec. 7, 1954 B. GASPAR ETAL 2,696,438

LIGHT SCREENING PHOTOGRAPHIC LAYER Filed April 11, 1950 EMULS/N EMULS/O/V .SUP/@OPT INVENTORS gLQIAJFTC RNEY Unite .pplication April-111950Seria1lN0; 155,362

*113L'Claims- (Cl`95-3) 4Theipresenttinyentionrelates toj-rdyes andhto =,their-use ainphotographiclight,fscreeninglayers.

' In the i preparatiomof.I sensitive Yphotographic materials, zqlitfisffrequetly desirableto provdei-foraonezor more flayers which are colored While the material.-,iswexposedito light,

j, but-colorless ..in=the processedzlmaterial. Numerous light .-1 screening materials such: as colloidal'y silver, lmethenil-bis- ,.pyrazolone metal. salts-of osazonew derivativesY ofi; dihyf i- 1 droxytartaric. iacid, lgaminocinnamylidene ammonium qualternary salts, auraminealetc. have .been1 proposediiforeuse f in "photographic llter or. ant-ihalation -layers. fSome z of -llthese coloring materials are' removed byrwashng in. aqueous processing-baths, others -are' converted into colorless 'y products in `said baths,while1-still others-canbelbleached i out 1 only by l solutions having#i detrimental iffe'ctsf: on 'lthe photographic layery the -latentimage; the Vdeveloped @image-or in colorphotography--thelimage-formingdyes. f-1the light Vscreenir-g' materials I lier'etofo're1 Il cnown 1Many -L o r`screening dyes are decolorize'd finff alkaline .developersV i or .neutral fixing baths {wherebyf'they are rendered useless@ in freversalematerials Wherev their ypresence is desiredf lduring the 'seconds exposure. fjFor- `example,-"the dye `lauramine, mentioned above, is Washed 'out from photographiomaterials in' neutral processing Abaths/Still -fother dyes act V'as color formers 'or theysplit in` thedeveloperor-xing bathto form compounds which act as .c olor v forrners; i. e.,

-compounds which later 'on react with colorltdevelopers' or diazo compounds to form' stabledyes.

Itis,l therefore.. any objectof the presentfinvention to .provide dyes for light screening 'layers' vvhichdo not have kthe' `above named undesirable' properties; yiz.,1Wh ich-do not' desenstize 'photographic' emulsions-and donot diffuse within thephotographiczcolloid,y Whichf do "not 'react' with dye components such as `color` developers andj' Ad it 1zo joompounds, and which can be destroyed 'to"'f0rm"'pro'ducts which in general do not react With said dye components; which are. not destroyed in the rst processing stages, but Whichcan be destroyed in later processing stages bymsteps .fmmpatible with ,the photographic materialand image.

"In the o-per'iding'pplication entitledPhotographic 'Process-fand Material Serial No."`1'55,363, iiled on"April 1l,"l950,it is disclosed that compounds --f'and the-*salts thereof, where, :X,-Y and .Z stand' for. hydro- '..carbon and'gsubstituted hydrocarbongradicalsyan 'De-used i as dyesl in @light screening -fphotographics-layers. These dyes, schf asketimi-nes fandfquinoneimines, are e relatively stable in alkalineandneutral processing-.baths.but-isplit in aclid lbaths with `formation of '-theI products X-CO-Y 'outA from thesephotographiccolloid.

We lhave found.- thatz the rsalts yof k'etimines .adhering to the" abovetformula'wherefX- .and Y; stand-for para y'amino aryltresid'ues and substituted derivatives thereof-fandfwliere Zi-has the 'abowefexplained meanin f' ht-.flscreeliingiphotogtephif.

gf,sare:particularlysyalublecompounds'rfor dyeing 11g yers. ZIii suitable tresidues@ X; IY -'andtZ-'are .choSeIL :these Sms Patent C) "ice dyes do not desensitize silver halide emulsions; they are fast to diffusiongor'they can vbe rendered non-diffusing by the additionof suitableprecipitatingagents; they are relatively stable in-alkaline and neutral media butare easily decolorized in acid processing bath s thesedyes;the products X-CO-Y and most lof the products Z-NHz formed when they are decolorized,'do"n0t react with color S developersy in :'the presenceof-xdevelopable 'silver' .onfwith diazo compounds; .theyrcanbe .produced-lin a wide=range .of-"colors ywhich excel. in brlliancy, i. e., theyy absorb inar- I row Vspectrali bands!J and, therefore, `filters ther ilight. yvery ratedinto photographie colloids. Photographicmaterials containinghese 1' dyes, .fwhileftheyl are easily ydecolor-ized in acidftreating baths, do.notfaderbyageingunder normal conditions. Furthermore-,LV in processeswhichzrequireiacid processing baths to produce dye images,11sucl1,asintthe `process describedi .in IU. IS. fr Patent'. 2,0.20775, no 1 additionalf processing" step-:to destroy: the light screeningfketi- .mines of thepresent2 invention' is required, the destruction .of l'the ketimine bei-ng` performed .simultaneously With'f the local bleaching ofzthe ,image .forming dyes, e.;-- g.; 1in the v. acid baths "disclosed in UL S`.f-Patent'Re.122,308. tj Howrf ever; the destrutionof' thelketiminem'ay befperformed l in a separate acid bath if desired.

:Suitableketiminesto be incorporated into photographic jlight' screening 'layers-are: e; g., -the imino-substitutedide- \rivatives 'of auramine. f-While auraminerit'selfbas all relmarkable '-`st`abilitytowards hacids; most: "immo-substituted auramines are easily hydrolized in acidi-media. 'fFor example, a 0.01%;'solution 0f N-phenylauramine in l-normal sulfuric acid becomes#'colcirless after two minutes Whereas a 0.01% )solution-of auramine under the same conditions is stillicolored after'fo'rty minutes.

30 The imino-substituted auramines are prepared by alkylating auramine ba'sevwith alkylating agents such as alkyl halides, by melting auraminevwith:aliphatic or aromatic amines or salts thereof, by combining Michlers ketone with-amines in ithe lpresence#of;tcondensatingeagents; by combining 4,4 bis (dimethylamino)diphenylmetbane with amines in the presence of oxidizing agents or by condensing N-substituted 4''dim"etby1a minobenzamides with dimethylailine.

If the: Michlers ketone or the auramine in these reactions is replaced-'with other compounds of the same class .suchs as ,the fauramines. of German; Patent 6 85004 and Ithe ketones. of...German- Patenti 282108,? compounds of similar properties are obtained. It is possible,`there fore, tomroduce immo-substitutedauramines Where the "D residues of the above formulaistand for Ll-aminophenyl4 ,radicals vvh-ich-may`\contain substituents in the phenyl residue and where the 4,-amin0 group has secondary or tertiary character. rl`he hydrocarbon residuesat- 5,' tached'to theamino groupinthe"4-aminophenyl radicals D may be substituted or unsubstituted and, among the substituted hydrocarbon residues, We prefer those which carry solubilizing groups. Suitable starting materials in the preparation of solubilized auramines are e. g., the products"ob tained bv alkylating 4,4'-diaminobenzophenone or 4,4di-(monoalkylamino)benzopbenones with chloroacetic acid or with bromohydrin or with sodium 2-bromoethane -l-sulfonate. It is furthermore possible to quaternate at least one of the 4 -dialkylaminophenyl radicals by j reacting either the intermediate `ketone orl'the'fimino-sub- "stitutd '"-auramine' v vith analkylating ,v a'gent. f g., a water-soluble yellowsalt Whiclifis supposed to- ,contain a i `quater-nary 'group .,.eqniniolecplar p9 1o of methyl-.benzenes'ulfonate ---Ol5par.ticul ar yte reigthe guaternary., .compo d Sores-,chloroaeetic e moethauesulfoni ...acd-Ef-g.. :fbyfnteltinguremin vfrbeastiidineand. by melting the intermediate thus obtained with sodium bromoethane tained by condensing two mol equivalents of sodium sulfonate, a compound is formed which is believed to bisulte with one mol equivalent of crotonaldehyde. adhere to the following formula By this treatment a substitution of the external amino group in the residue Z is achieved whereby the dye (CHWNG 5 becomes soluble in alkali and difcultly soluble or insoluble in weak acids. It is assumed that, in neutral. /C'N 002B or weakly acid conditions, the acidic substituent forms (Griggsan inner salt with one of the basic groups which are l present. in the molecule. These dyes which carry at least CHVCHVSOB. l one acid group can be incorporated with particular ease from their alkaline solutions into a colloid such as gei- This compound forms easily soluble alkali salts, e. g., it atm The effect of a Solubilizing group in the residue Z dissolves in an aqueous bicarbonate solution to form a is Similar t0 the eieot of a solubilizing group in the stable solution which, upon neutralization with a weak residuesXand/Or y, acid suqh as acetic acid forms an inselublestable preipii The auramines which have external amine groups in 'late 0f ll'lienSely yelley Color: UPOH aeldll'leallejl With e the residue Z are converted, by treatment with one or strong ae1d,th1s precipitate dissolves t0 ferm an intensely more equivalents of a solubilized alkylatihg agent such yellOW SOlullel'l Wllleh, Wl'fllll a mllll'fe,- b eCOmeS C'Olef' as sodium bromoethanesulfonate, into products the propless -Other Compounds Obtamed fremmlnojsilbstltuted erties of which are similar to the quaternery products diseufemlnee and elkylalmg egeIlS Calfylflg aCICllC gTOUPS closed above. These products may contain one or mole behave Slmllaflyof said solubilizing substituents in said external amine The substituent Z in the above formula can be varied group of the residue Z, and/0r in the amino groups of within wide limits. If Z is a phenyl residue carrying an the residues X and Y, amino QTQUP 1U direct lllllage t0 the Phel'lyl IeSldlle SUCll The auramines of the present invention are wealth es 1H l'dlmeihylellllflepllenylaufamme, ille leSUl'flHg dye 25 colored bases and form, with acids, intensely colored saltsA 1S Orapge 01 reilother red dyes are fhOSe Where 1S Those auramines which are not solubilized are dissolved e Pylldlile 01 'flllaele H UeleuS, e: go 'Il le dyeS Ob'alled in water with one or two equivalents of an acid such by melting auramine Wl'fll Z'amlflOPyflfllllje 0r Wlth 2- as acetic acid; the solution is added to a gelatin .solution aminothiazole. Yellow dyes are obtained if Z is an unand the dyed gelatin, brought to the desired pH, is coated substituted hydrocarbon rediCal SUCh aS in N-dOdCCylto form a layer of the photographic material. The auramine, N-phenylauremme, N-4b 1p her1ylv1auremine, auramines which are void of acidic substituents, hereinA N-vL- Haplltllylaufemllle- Those eQmPl'lSlHg all alkyl radlafter designated as basic auramines and which might Cal 1n OrtllfePOSlllOfl 0f the SubStlUent Z Such 2S OrihO- diffuse, such as o-tolylauramine, can be precipitated vith tolylauramine high molecular weight acids after they are incorporated X into gelatin, to form non-diffusing salts. Suitable h. gli molecular weight acids or salts thereof are e. g., tanrjc N=C acid, dodecylsulfuric acid and sodium 4,4di(pheny X ureido)stilbene-2,2'-disulfonate The addition of a higl Hs molecular weight acid or a salt thereof to the dyed 40 colloid not only helps to avoid diffusion but has the X=(CHt)2N-C further advantage of stabilizing the salt form of 'the auramine; i. e., while the acetate of ari auramine might (from o-toluidine and auramine) or 3,3dimethyl4- dissociate in gelatin, producing therein the weak color aminobiphenylylauramine of the auramine base, the salt of the auramine with the X Ll5 high molecular weight acid incorporated in gelatin, has

/ the intense color typical of the salt.

NH2- N=C Colloids containing simple irnino substituted basic I \X auramines should have a low pH in order to show thc CH3 CH3 color of the auramine salt. However, as a light sensi- Ell tive photographic material permits pH-variations only within certain limits, it is necessary to stabilize the salt color at a pH which is compatible with the adjacent light (from o-tolidine and auramine, molecular proportion 1:1) or 3,3-dimethylbiphenylylidene-f,4bis-aurarnine X X sensitive emulsion. This can be achieved either by the \C=N C N=C/ addition of a precipitating acid as above, and/or by suitable substitution in the auramine molecule. We X CH E X found that gelatiris containing auramines with esternal 3 i strongly basic groups, such as N-l4(tu-piperidinoethoxy) (from o-tolidine and auramine, molecular proportion phenyl] auramine,

Hz H2 /C C\ [(CHs)z-N-]C= `CyO--ClIt---CHT-N CH2 CC H2 Ha 1:2) are yellow dyes which are remarkably brilliant are intensely colored and particularly brilliant at a reland decompose with particular ease in acid baths. Ether atively high pH (e. g. pH=6.5) whereas gelatins congroups in position ortho or para have an effect similar to taining, in equivalent amounts, the corresponding aurthat of the ortho alkyl groups. These compounds are amines devoid of said external groups require a lower obtained e. g., by melting auramine with 4,4diamino pH (e. g. pH=4.8) to produce a yellow color of the diphenyl ether (molecular proportion 1:1 or 2:1) or with same intensity. 'The external basic group in the auro-anisidine or with di-4-arninophenyl ethers of poly- 75 amine molecule or the presence of a precipitating acid in ethyleneglycols or with 4-amino-4-(dibutylamino)di the gelatin does not interfere with the instability of the phenyl ether. Those dyes of the present invention which dye in strongly acid processing baths. have external amino groups in the residue Z, such as The auramines of the present invention which have 3,3 dimethyl 4 aminobiphenylyl (4) auramine, an acid function can be dissolved as alkali salts, e. g., in mentioned above, can be converted into acid substituted a sodium bicarbonate or tertiary phosphate aqueous soludyes by one of the following methods: either the comtion, the solution is then added to the gelatin and neutralpounds are acylated with derivatives of polyfunctional ized with an equivalent amount of acetic acid. lt is furacids such as succinic anhydride, naphthalene-l-sulfo thermore possible to dissolve basic auramines or the chloride-S-sulfonic acid and benzoic acid m-sulfo-chloride, auramines which carry acid groups in organic solvents or they are condensed with aldehyde biuulte compounds B5 such as alcohol and acetone, and to stir the solution into such as formaldehyde bisulte and the compound obthe gelatin. Suitable organic solvents in this procedure n t. f. ont., A .splunonns preparedgb are non-volatile dispersingagents such as high molecular Weightpolyethyleneslyeol on mixtures.. Qfmthesetd' ners- ;.inaagntswh oth .,...ris surh .21.;,a1cQhb1g0 er- MoSt.Qf;.-the .acid Substitutbdeur..

.QSe-Whinddcafbepr... piat'ed, ing agents!:sachas=desribed1n;U. aient 2,317A 84 Ammer mthodonsistsairnthe prelrltation ,0f substituted aurarnnefwithabasle .t

"A" oll'oid comprising-the ketiminesgpffjthiinvention stated asablayer ortoplaver fari-.in amultilaaerlmaterial, .fas`..inrerlayer. 1 Thel..l, etrnii1e. may;.benQQrpQtated sensitive silver halide layer itse'li prima layer` adlaev), to a sensitive silver halide layer. A photographic ma- 4, ,l 6 etiniwhiehraftemarfdsiisstleut. lizedfbvftasiditiqra-otftml- .aofi umnormal'; aetefaeid. .isf L as; a lter layer, on top of the green sensitive emulsions-layer. ,ls-Arlayeriofaan unsensitized: aston .-containingt l,1AT.-L2,2tfrlis lfodmhenyleo lfpyrazolone ,:5 ,-.eairboxvlc tal 3 l@ biguanidobenzylalcohol acetate Aon., of the filter layer.

Microscopic examination of across section of the fixed .1, may ,bepcoatei as` ,backing ,911, a str1/)portl org it m'av beJLlOpf out rmaterialrishowsthat pthe; auramine-tderivativehasqvnct n' dilusedifnto: fthe: feolorles adjacent lai/ers.

A; vmaterial fcontainingf vmlif'of fthe stockisolutpny-xof ...theiirst-exampletper square meterthasfardensityof abput ^r2ioatt40fmuna slight-lvfhighen.densityflatffturnufand a terial may comprise a-^light-=creening element according; fl-densityfofrpnly 0:15amy -540,fm u.

nelements. g E7zg.,lve layers,\arec,v,; vated A onl ay `supporti.l in ajrthefsllowingfrderr l litg-panehromaticsilver halide.. emulsion. W2; Ajcolloid comprising a'red iilterdye. 3. l Anf lortho'chromaticsilver i yhalide.l sernulsion. l 4.Avcoll-Gid1comprising a yellow ketimine.

5. An unsensitized silver(..ghal-idea4 emulsion.

, The ,layers numbered; 1,: `3 L 5 rnaymolg, may-y not `ecgntain 25 1 compound-1in.: ther topf-layers;

simagettfnrming dieser .dyegcomponents 'The ketinine's are mostly usedrinmsiich,as goncentration as to produce anoptical density 'of between' 1.0 and 3.0 at the wavelengtlr- @f1-'maximum absorption. The

ggguantityaof.dyet:requiredtopproduce `such density? is;;;30f\fproporti0n^.'to thegmetalliesilven presentan A mixture v off'equimoleclular parts.ofyaunaminembase and of ethylene-glycolabisflaminpphenvl) ,elther; is melted untilt the-,evolutionf,of Aammo I tiameeases. Y"The .smelt colasifstiz-lgr otra.. componndlhavipg rheg-`ormu1a ,120" bath contain :gsialrninutes zdye. Thereaften the,f-inaterialfis-iltreatedl ,fin av-1.bath..containing'5% sulfuri ftfbremiden 11%eifthiocarbamidegan ,t

quinoxaline whereby the three azo estare e yellow ,.aramine; '5 derivative is ditluse-ly; .-fldestroyed. After fthe .tftresidual' silver 4aisrxrernwed in :knovvnmanner; 1 the ,g f

is bathed in a diluted sodiumparbqnatefbath to ,s tabilize the appropriate color. valueuoftlie pH-sensitive azo dyes,

`35 and a photograph inenatur'al colors is obtained.

is alkylated with three-equivalents of sodium l-bromoi..etlnarle- Zgsulfonate. Ayyellow dyel can be,.,is9lat ed in 'f ,theformfits C,2,1,1 .=.i1,11r1` Salt- Y ...A .Stocksplution Of'rhisdyeis preparedf yiissolving oner gramV3 of the, ealciumsalt' ini `2() mh .1 .normal ,so'duinit 'bicarbonate solution. Ille g-sollutiong'zthus "9b- Atained isfreedfrom smallarnounts pf iumgcarvbonate byfltration- T hey Solutionris.. ,Stable at 'mom'.terpnerature, but prolong@daheating` Should.. be `af0ideddf, in the'above alkylation, Qnlyjpne or ,twon eguivalents f .ofsodium bromoethanesulfnate lwere d sdyes of sirni ilary properties, .arejobtained 1 IIt is be that part, of the .-ZGHa-.eQH2r-S0l groupsrontamed :these dyes are bound to a dimethylamiuo,,groupmandg partjtojme external amino group.

"Example: 2

fGompounds having :similarzgproperties zareobtaiuedwby L 1epl 'rcing theisodiun .-:bromoe'thane :sulfonatewfrthe .r-foregoing example ewith tben-zoie. acid;mfsulfochloridenwhgref.. y, atcompoundis.'obtained.` which is :supposediftoladhere sto; ther following :formula 1. EtQ-HQQN.

ethno/l)fphenylaurammef .Example- 3 A; silver: bromideemulsion,l vsensitized tto redtlight'. and

naphthol is coatedx ony a. transparent lsupport. Asecpnd -silver-bromide fem'ulsion, ...sen,siti z ed,.to .`4 Agreeng.,lig-ht and Lgico glp. etadecylamino a hthalenngisgcoated,there- 'dipg ZQLmLQo he took solution of the lirstexampl ...Dianeother.:sompsundsptith@nahm/elSt'JOHQr/szanaloithe-aurarnine derivative isf "discharged-anditghereafterv by the above described A bleaching f v bath. v`vwhereby-fr the 1 .azo

14:45. ldyes are bleached.

Example, 6

:30:: basic, auramine. Suitable- 4basic aura-minesare `e. g., o-

gous methods.

The variousgures in'the accompanyingidrawingfrepresent enlarged sectionalfgviews--of photographic elements aina.. 'ght.Qr.eening-.layers.nacordarledvith..thein rilmatedwith an Si tween emulsion layers 14 and 15 is a light screening layer 16 containing a ketimine salt according to the invention.

We claim:

l. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid with a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an organic radical connected to the N atom through a carbon atom, said compound being easily hydrolysable under photographic processing conditions.

2. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising an essentially non-diitusing salt of an acid with a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an organic radical connected to the N atom through a carbon atom, said compound being easily hydrolysable under photographic processing conditions.

3. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid with a basic auramine of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an organic radical connected to the N atom through a carbon atom, said compound being easily hydrolysable under photographic processing conditions.

4. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising an essentially non-diffusing salt of an acid with a basic auramine of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an organic radical connected to the N atom through a carbon atom, said compound being easily hydrolysable under photographic processing conditions.

5. A photographic material including a light sensitive silver halide containing layer and comprising an inner salt of a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an organic radical connected to the N atom through a carbon atom, said compound comprising at least one group having an acid function and being easily hydrolysable under photographic processing conditions.

6. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising an essentially non-diffusing inner salt of a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an organic radical connected to the N atom through a carbon atom, said compound comprising at least one group having an acid function and being easily hydrolysable under photographic processing conditions.

7. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid With a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an organic radical carrying a basic group, said organic radical being connected to the N atom shown through a carbon atom, said compound being easily hydrolysable under photographic processing conditions.

8. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid with a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an aromatic radical of the benzene series carrying an ether group in one of the positions 2 and 4 with respect to the N atom shown, said compound being easily hydrolysable under photographic processing conditions.

9. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid with a cornpound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is an organic radical carrying at least one acid group, said organic radical being connected to the N atom shown through a carbon atom, said compound being easily hydrolysable under photographic processing conditions.

l0. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid with a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is a hydrocarbon radical carrying an amino substituent having at least one of the amino hydrogens replaced by an organic radical carrying at least one external group having an acid function, said compound being easily hydrolysable under photographic processing conditions.

ll. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid with a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is a hydrocarbon radical carrying an N acyl amino radical carrying an external acid group, said compound being easily hydrolysable under photographic processing conditions.

12. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid with a compound of the formula:

wherein X is a paraamino substituted phenyl radical, the amino group of which carries from one to three organic radicals bonded thereto through a carbon atom in addition to the phenyl radical and Z is a hydrocarbon radical carrying an amino substituent having at least one of the amino hydrogens replaced by a substituent -RA wherein R is a bivalent hydrocarbon radical and A is an acid group, said compound being easily hydrolysable under photographic processing conditions.

13. A photographic material including a light sensitive silver halide containing layer and comprising a light screening layer comprising a salt of an acid with a compound of the formula:

I spouse References Cited in the le of this patent 9 CH,N.

/C=No-CHCHr-B| Number (CHzN 2,143,786 2,203,659 wherein B is a radical selected from the group con- 2,293,733 sisting of NI-I2, -NH alkyl, -N--dialkyl and 2,390,707 m @fraaie "Nu 215001045 wherein X stands for the atoms which serve to com- 2533472 plete a ring, said compound being easily hydrolysable under photographic processing conditions. 15 Number UNITED STATES PATENTS Name Date Mannes et al Jan. 10, 193.9 Sheppard et al June 4, 1940 rooker Oct. 13, 1942 Heimbach Dec. 11, 1945 Rohrmann Nov. 30, 1948 Dorman Apr. 26, 1949 Sawdey Mar. 7, 1950 Keyes et al Dec. 12, 1950 FOREIGN PATENTS Country Date Great Britain June 2, 1938 Great Britain Sept. 16, 1943 Great Britain May 6, 1949 

1. A PHOTOGRAPHIC MATERIAL INCLUDING A LIGHT SENSITIVE SILVER HALIDE CONTAINING LAYER AND COMPRISING A LIGHT SCREENING LAYER COMPRISING A SALT OF AN ACID WITH A COMPOUND OF THE FORMULA: 